The prior art is replete with apparatus for filling containers with a fluid material as the containers are rotated about a fixed axis. Generally, one or more plunger nozzles are moved toward and into contact with or in proximity to the rim of the rotating mold or container which is to be charged with fluid material. The material flows either by gravity or under a forced pressure. A fluid indicator measures the volume of material delivered to each container.
Apparatus of this type has been subject to certain problems and disadvantages. Among these are problems arising during filling, namely the tendency of the nozzle which depends to or is moved into proximity with the rim of the container or mold, sealing the same during filling. The result may be internal container or mold pressurization and agitation of the material therein. If the material is of a somewhat viscous nature having a tendency to set-up when delivered from heated to cooler ambient surroundings the agitation with set-up may militate against proper settling of material. Further, the viscous filling material may tend to entrain or trap air within the container or mold as the filling operation is carried out. Neither of these occurrences may be tolerated in the processing of lipstick pomades having as one requirement a smooth, aesthetically attractive outer surface.
A further problem and disadvantage resides in the manner and means to control the flow of material thereby to introduce an identical charge to each mold or container. To this end it is necessary and required that each container be charged with no less than a specified volume.
Other problems and disadvantages of like concern although not discussed hereafter are recognized in connection with other prior art forms of filling apparatus.